1 files changed, 141 insertions, 37 deletions

diff --git a/activerecord/lib/active_record/connection_adapters/abstract_adapter.rb b/activerecord/lib/active_record/connection_adapters/abstract_adapter.rb
index 0fe868478c..dc970c384b 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract_adapter.rb
@@ -76,8 +76,8 @@ module ActiveRecord
 
       SIMPLE_INT = /\A\d+\z/
 
-      attr_accessor :visitor, :pool
-      attr_reader :schema_cache, :owner, :logger, :prepared_statements, :lock
+      attr_accessor :pool
+      attr_reader :visitor, :owner, :logger, :lock, :prepared_statements
       alias :in_use? :owner
 
       set_callback :checkin, :after, :enable_lazy_transactions!
@@ -100,6 +100,19 @@ module ActiveRecord
         end
       end
 
+      def self.build_read_query_regexp(*parts) # :nodoc:
+        parts = parts.map { |part| /\A[\(\s]*#{part}/i }
+        Regexp.union(*parts)
+      end
+
+      def self.quoted_column_names # :nodoc:
+        @quoted_column_names ||= {}
+      end
+
+      def self.quoted_table_names # :nodoc:
+        @quoted_table_names ||= {}
+      end
+
       def initialize(connection, logger = nil, config = {}) # :nodoc:
         super()
 
@@ -108,11 +121,10 @@ module ActiveRecord
         @instrumenter        = ActiveSupport::Notifications.instrumenter
         @logger              = logger
         @config              = config
-        @pool                = nil
+        @pool                = ActiveRecord::ConnectionAdapters::NullPool.new
         @idle_since          = Concurrent.monotonic_time
-        @schema_cache        = SchemaCache.new self
-        @quoted_column_names, @quoted_table_names = {}, {}
         @visitor = arel_visitor
+        @statements = build_statement_pool
         @lock = ActiveSupport::Concurrency::LoadInterlockAwareMonitor.new
 
         if self.class.type_cast_config_to_boolean(config.fetch(:prepared_statements) { true })
@@ -125,27 +137,51 @@ module ActiveRecord
         @advisory_locks_enabled = self.class.type_cast_config_to_boolean(
           config.fetch(:advisory_locks, true)
         )
-
-        check_version
       end
 
       def replica?
         @config[:replica] || false
       end
 
+      # Determines whether writes are currently being prevents.
+      #
+      # Returns true if the connection is a replica, or if +prevent_writes+
+      # is set to true.
+      def preventing_writes?
+        replica? || ActiveRecord::Base.connection_handler.prevent_writes
+      end
+
       def migrations_paths # :nodoc:
         @config[:migrations_paths] || Migrator.migrations_paths
       end
 
       def migration_context # :nodoc:
-        MigrationContext.new(migrations_paths)
+        MigrationContext.new(migrations_paths, schema_migration)
+      end
+
+      def schema_migration # :nodoc:
+        @schema_migration ||= begin
+                                conn = self
+                                spec_name = conn.pool.spec.name
+                                name = "#{spec_name}::SchemaMigration"
+
+                                Class.new(ActiveRecord::SchemaMigration) do
+                                  define_singleton_method(:name) { name }
+                                  define_singleton_method(:to_s) { name }
+
+                                  self.connection_specification_name = spec_name
+                                end
+                              end
       end
 
       class Version
         include Comparable
 
-        def initialize(version_string)
+        attr_reader :full_version_string
+
+        def initialize(version_string, full_version_string = nil)
           @version = version_string.split(".").map(&:to_i)
+          @full_version_string = full_version_string
         end
 
         def <=>(version_string)
@@ -177,9 +213,13 @@ module ActiveRecord
         @owner = Thread.current
       end
 
+      def schema_cache
+        @pool.get_schema_cache(self)
+      end
+
       def schema_cache=(cache)
         cache.connection = self
-        @schema_cache = cache
+        @pool.set_schema_cache(cache)
       end
 
       # this method must only be called while holding connection pool's mutex
@@ -230,6 +270,11 @@ module ActiveRecord
         self.class::ADAPTER_NAME
       end
 
+      # Does the database for this adapter exist?
+      def self.database_exists?(config)
+        raise NotImplementedError
+      end
+
       # Does this adapter support DDL rollbacks in transactions? That is, would
       # CREATE TABLE or ALTER TABLE get rolled back by a transaction?
       def supports_ddl_transactions?
@@ -308,12 +353,18 @@ module ActiveRecord
       def supports_foreign_keys_in_create?
         supports_foreign_keys?
       end
+      deprecate :supports_foreign_keys_in_create?
 
       # Does this adapter support views?
       def supports_views?
         false
       end
 
+      # Does this adapter support materialized views?
+      def supports_materialized_views?
+        false
+      end
+
       # Does this adapter support datetime with precision?
       def supports_datetime_with_precision?
         false
@@ -350,10 +401,31 @@ module ActiveRecord
         false
       end
 
+      # Does this adapter support optimizer hints?
+      def supports_optimizer_hints?
+        false
+      end
+
       def supports_lazy_transactions?
         false
       end
 
+      def supports_insert_returning?
+        false
+      end
+
+      def supports_insert_on_duplicate_skip?
+        false
+      end
+
+      def supports_insert_on_duplicate_update?
+        false
+      end
+
+      def supports_insert_conflict_target?
+        false
+      end
+
       # This is meant to be implemented by the adapters that support extensions
       def disable_extension(name)
       end
@@ -431,6 +503,9 @@ module ActiveRecord
         #
         # Prevent @connection's finalizer from touching the socket, or
         # otherwise communicating with its server, when it is collected.
+        if schema_cache.connection == self
+          schema_cache.connection = nil
+        end
       end
 
       # Reset the state of this connection, directing the DBMS to clear
@@ -443,11 +518,9 @@ module ActiveRecord
         # this should be overridden by concrete adapters
       end
 
-      ###
-      # Clear any caching the database adapter may be doing, for example
-      # clearing the prepared statement cache. This is database specific.
+      # Clear any caching the database adapter may be doing.
       def clear_cache!
-        # this should be overridden by concrete adapters
+        @lock.synchronize { @statements.clear } if @statements
       end
 
       # Returns true if its required to reload the connection between requests for development mode.
@@ -473,15 +546,21 @@ module ActiveRecord
         @connection
       end
 
-      def case_sensitive_comparison(table, attribute, column, value) # :nodoc:
-        table[attribute].eq(value)
+      def default_uniqueness_comparison(attribute, value, klass) # :nodoc:
+        attribute.eq(value)
       end
 
-      def case_insensitive_comparison(table, attribute, column, value) # :nodoc:
+      def case_sensitive_comparison(attribute, value) # :nodoc:
+        attribute.eq(value)
+      end
+
+      def case_insensitive_comparison(attribute, value) # :nodoc:
+        column = column_for_attribute(attribute)
+
         if can_perform_case_insensitive_comparison_for?(column)
-          table[attribute].lower.eq(table.lower(value))
+          attribute.lower.eq(attribute.relation.lower(value))
         else
-          table[attribute].eq(value)
+          attribute.eq(value)
         end
       end
 
@@ -503,10 +582,30 @@ module ActiveRecord
         index.using.nil?
       end
 
-      private
-        def check_version
+      # Called by ActiveRecord::InsertAll,
+      # Passed an instance of ActiveRecord::InsertAll::Builder,
+      # This method implements standard bulk inserts for all databases, but
+      # should be overridden by adapters to implement common features with
+      # non-standard syntax like handling duplicates or returning values.
+      def build_insert_sql(insert) # :nodoc:
+        if insert.skip_duplicates? || insert.update_duplicates?
+          raise NotImplementedError, "#{self.class} should define `build_insert_sql` to implement adapter-specific logic for handling duplicates during INSERT"
         end
 
+        "INSERT #{insert.into} #{insert.values_list}"
+      end
+
+      def get_database_version # :nodoc:
+      end
+
+      def database_version # :nodoc:
+        schema_cache.database_version
+      end
+
+      def check_version # :nodoc:
+      end
+
+      private
         def type_map
           @type_map ||= Type::TypeMap.new.tap do |mapping|
             initialize_type_map(mapping)
@@ -580,14 +679,12 @@ module ActiveRecord
           $1.to_i if sql_type =~ /\((.*)\)/
         end
 
-        def translate_exception_class(e, sql)
-          begin
-            message = "#{e.class.name}: #{e.message}: #{sql}"
-          rescue Encoding::CompatibilityError
-            message = "#{e.class.name}: #{e.message.force_encoding sql.encoding}: #{sql}"
-          end
+        def translate_exception_class(e, sql, binds)
+          message = "#{e.class.name}: #{e.message}"
 
-          exception = translate_exception(e, message)
+          exception = translate_exception(
+            e, message: message, sql: sql, binds: binds
+          )
           exception.set_backtrace e.backtrace
           exception
         end
@@ -600,24 +697,23 @@ module ActiveRecord
             binds:             binds,
             type_casted_binds: type_casted_binds,
             statement_name:    statement_name,
-            connection_id:     object_id) do
-            begin
-              @lock.synchronize do
-                yield
-              end
-            rescue => e
-              raise translate_exception_class(e, sql)
+            connection_id:     object_id,
+            connection:        self) do
+            @lock.synchronize do
+              yield
             end
+          rescue => e
+            raise translate_exception_class(e, sql, binds)
           end
         end
 
-        def translate_exception(exception, message)
+        def translate_exception(exception, message:, sql:, binds:)
           # override in derived class
           case exception
           when RuntimeError
             exception
           else
-            ActiveRecord::StatementInvalid.new(message)
+            ActiveRecord::StatementInvalid.new(message, sql: sql, binds: binds)
           end
         end
 
@@ -631,6 +727,11 @@ module ActiveRecord
             raise(ActiveRecordError, "No such column: #{table_name}.#{column_name}")
         end
 
+        def column_for_attribute(attribute)
+          table_name = attribute.relation.name
+          schema_cache.columns_hash(table_name)[attribute.name.to_s]
+        end
+
         def collector
           if prepared_statements
             Arel::Collectors::Composite.new(
@@ -648,6 +749,9 @@ module ActiveRecord
         def arel_visitor
           Arel::Visitors::ToSql.new(self)
         end
+
+        def build_statement_pool
+        end
     end
   end
 end